1. Field of the Invention
The present invention relates to a three-dimensional image creating apparatus for creating a three-dimensional image based on a two-dimensional image by using computer graphics.
2. Description of the Related Art
Conventionally, a method for creating various three-dimensional images with the use of computer graphics has been developed. Such a method is one of the most basic methods that comprises the steps of defining a three-dimensional shape by space coordinates, and displaying a state viewed from an arbitrary direction as a three-dimensional image projected on a two-dimensional plane by rendering.
Moreover, by using a two-dimensional image drawing tool called as "paint", it is possible to draw a picture on a display screen of computer graphics with a feeling such that a user actually draws a picture with a paintbrush or the like. Also, by applying a pictorial method capable of giving three-dimensional and perspective effects to a picture to be drawn, it is possible to draw a three-dimensional image.
In order to obtain a three-dimensional image, there is a method of inputting space coordinates which express a three-dimensional shape. However, according to the method, in the case where the three-dimensional shape is complicated, the number of required space coordinates increases, and consequently it is difficult to give definitions and input these space coordinates. Further, in a shape as smoothly modifying, it is difficult even to determine space coordinates. Furthermore, a designer is hard to grasp a relation between a spatial shape sensitively imaged and a geometric shape expressed by numerical coordinates. In particular, in the case of making a modification to the spatial shape, it is necessary to make modifications to coordinates which define the shape, which modifications are very troublesome.
According to a method of directly drawing a three-dimensional image with the use of the drawing tool of computer graphics, an operator who draws a picture, requires a picture drawing ability. The three-dimensional image thus created is usable in only limited range such as modification of display colors.